A novel bud sport from the ‘Benitaka’ table grape cultivar (Vitis vinifera L.) improves sugar and anthocyanin accumulation at the berry ripening stage

Abstract

Background‘Early-ripening Benitaka’ (Vitis vinifera), a bud sport of ‘Benitaka’ was found in 2008, which ripens earlier than its parental line. Differences in sugar and anthocyanin content and the relevant sucrose and anthocyanin metabolic enzymes for the two cultivars were investigated during fruit ripening. ResultThe mutation made berry size, reducing sugar of pulp and anthocyanin of pericarp increases during fruit ripening. In both ‘Benitaka’ and its mutant, the cell wall invertase activity was similar at the onset of ripening, but it showed markedly higher activity in the mutant at the late stage, which were correspondingly associated with the higher transcript level of cell wall invertase. For soluble invertase, the activity showed no difference between mutant and ‘Benitaka’ during the early stage of berry development, and dropped to the lowest level around the onset of ripening. Interestingly, the mutant had a greater reduction than its parental cultivars in the activity of soluble invertase. In addition, the expression level of the UDP-glucose: flavonoid 3-O-glucosyltransferase (UFGT) gene after veraison was higher in the berry pericarp of the mutant compared with that of the ‘Benitaka’, in agreement with the higher anthocyanin content of the former. ConclusionThe mutation in ‘early-ripening Benitaka’ affected sugar and anthocyanin metabolism, which might be related with accumulation of sugar and anthocyanin and other early-ripening phenotypes.